1. Field of the Invention
The present invention relates to a control apparatus of a DC power coupling system for exchanging power between AC power systems using voltage source type self-exciting power converters.
2. Description of the Related Art
A conventional apparatus has the following problems. Assume that two power converters are coupled to each other through a DC circuit, and one converter for regulating a DC voltage of the DC coupling circuit stops its operation due to, e.g., a failure. In this case, the other converter for regulating active power must stop its operation although an operation for exchanging reactive power between itself and an AC system connected thereto can be performed. Note that, even if the other converter for regulating active power stops its operation, one converter for regulating a DC voltage can continue its operation at an operating point where a direct current of the DC coupling circuit is set to be zero, and reactive power can be exchanged between one converter and the AC system connected thereto.